Development of a Combined Bulging-Piercing Technique to Reduce Forming Load for a Long Semi-Hollow Stepped Part

2022 ◽  
Author(s):  
Nara Nakeenopakun ◽  
Sutee Olarnrithinun ◽  
Yingyot Aue-u-lan
Keyword(s):  
Frictional Contact ◽  
High Load ◽  
Product Line ◽  
Thickness Variation ◽  
Main Concept ◽  
Forming Load ◽  
Backward Extrusion ◽  
Wall Thickness Variation ◽  
A New Technique ◽  
Very High

Abstract This paper aims to develop a new forming technique to manufacture a long semi-hollow stepped part. Traditionally, hot backward extrusion is used. This technique is not suitable, because it requires a very high forming load acting on the die and punch especially at the contact between punch and workpiece. As a result, the service life of the punch is very low. Therefore, a new technique to overcome this problem is needed. A combined bulging-piercing technique was proposed and developed in this research. The main concept of this technique is to bulge the part by upsetting the workpiece between the punch and the counter-punch to generate high frictional contact pressure which will help to restrain the material sliding down to the die cavity during the piercing step. In other words, this technique utilizes frictional force at the die-workpiece interface to reduce the forming load of the punch. Finite element modeling was employed to investigate and determine the suitable level of the bulging which can reduce the forming load without generating any significantly high force to the counter-punch. Only experiments with the minimum forming load were selected and implemented to validate this concept, because other conditions with high load will risk to damage the punch and the machine press of the product line. The results show that this technique can reduce the forming load by almost 40%, and also control a good concentricity of the part and reduce the wall thickness variation.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

Mechanics of Conventional Spinning

1963 ◽  
Vol 85 (4) ◽  
pp. 346-350 ◽  
Author(s):  
H. C. Sortais ◽  
S. Kobayashi ◽  
E. G. Thomsen
Keyword(s):  
Wall Thickness ◽  
Pure Aluminum ◽  
Tangential Force ◽  
Deformation Energy ◽  
Thickness Variation ◽  
Force Component ◽  
Commercially Pure ◽  
Conventional Spinning ◽  
Wall Thickness Variation ◽  
Experimental Values

In conventional spinning of cones, the cone-wall thickness variation was studied using blanks of 1100-0 commercially pure aluminum sheet of 0.050-in. thickness. The results revealed that the radial stress induced in the unspun flange is the major cause of nonuniform wall thickness of spun cones. The theoretical tangential force component was derived by use of the deformation energy method. Qualitative agreement was found between the theoretical and the experimental values of tangential force component in the underspinning conditions.

Fließpressen hohler Wellen mit Wanddickenvariation/Cold forging of hollow shafts with wall thickness variation – Numerical investigation of a hollow forward extrusion process with adjustable deformation zone

2020 ◽  
Vol 110 (10) ◽  
pp. 684-688
Author(s):  
Alexander Weiß ◽  
Mathias Liewald
Keyword(s):  
Numerical Investigation ◽  
Metal Forming ◽  
Extrusion Process ◽  
Cold Forging ◽  
Thickness Variation ◽  
Part Geometry ◽  
Forming Technology ◽  
Wall Thickness Variation ◽  
The University ◽  
Hollow Shafts

Die Fertigung von Hohlwellen mit komplexer Innengeometrie bedingte bisher meist aufwendige Prozessrouten. Ein am Institut für Umformtechnik der Universität Stuttgart entwickeltes Kaltfließpressverfahren soll nun die wirtschaftliche und flexible Fertigung von Hohlwellen mit Wanddickenvariation ermöglichen. In diesem Beitrag werden das Verfahren beschrieben und die Ergebnisse der numerischen Untersuchung des Einflusses der Werkzeugkinematik auf die erzielbare Pressteilgeometrie dargelegt.   Usually, the production of hollow shafts with complex internal geometry by cold forging requires extensive process routes. A novel cold forging process developed at the Institute for Metal Forming Technology at the University of Stuttgart allows for an economical and flexible production of hollow shafts. This article describes the manufacturing process and presents the results of a numerical investigation for determining the influence of tool kinematics on the achievable part geometry.

The Forming Characteristics of AA 2024 Aluminium Alloy in Radial Extrusion Process Combined with Backward Extrusion

2006 ◽  
Vol 519-521 ◽  
pp. 955-960 ◽  
Author(s):  
Dong Hwan Jang ◽  
J.H. Ok ◽  
G.M. Lee ◽  
Beong Bok Hwang
Keyword(s):  
Material Flow ◽  
Volume Ratio ◽  
Extrusion Process ◽  
Process Conditions ◽  
Forming Load ◽  
Backward Extrusion ◽  
Aa 2024 ◽  
Forming Characteristics ◽  
Frictional Condition ◽  
Simulation Results

Numerical analysis of radial extrusion process combined with backward extrusion has been performed to investigate the forming characteristics of an aluminum alloy in a combined extrusion process. Various variables such as gap size, die corner radius and frictional conditions are adopted as design or process parameters for analysis in this paper. The main investigation is focused on the analysis of forming characteristics of AA 2024 aluminum alloy in terms of material flow into backward can and radial flange sections. Due to various die geometries and process conditions such as frictional conditions, the material flow into a can and flange shows different patterns during the combined extrusion process and its characteristics are well summarized quantitatively in this paper in terms of forming load, volume ratio etc. Extensive simulation work leads to quantitative relationships between process conditions and the forming characteristics such as volume ratio of flange to can and the size of can and flange in terms of the can height extruded backward. It is easily seen from the simulation results that the volume ratio, which is defined as the ratio of flange volume to can volume, increases as the gap size and/or die corner radius increase. However, it is interesting to note that the frictional condition has little influence on the forming load and the deformation patterns. Usually, the frictional condition is a greatest process variable in normal forging operation. It might be believed from the simulation results that the frictional conditions are not a major process parameter in case of combined extrusion processes. It is also found that the can size, which is defined as the height of billet after forming, turns out to be even smaller than that of initial billet under a certain condition of die geometry.

Injection-Moulded Models of Major and Minor Arteries: The Variability of Model Wall Thickness Owing to Casting Technique

2005 ◽  
Vol 219 (5) ◽  
pp. 381-386 ◽  
Author(s):  
T O'Brien ◽  
L Morris ◽  
M O'Donnell ◽  
M Walsh ◽  
T McGloughlin
Keyword(s):  
Wall Thickness ◽  
Ccd Camera ◽  
Western Society ◽  
Experimental Investigations ◽  
Thickness Variation ◽  
Casting Technique ◽  
Radiological Images ◽  
Thickness Variability ◽  
Wall Thickness Variation ◽  
Integrated Technique

Cardiovascular disease of major and minor arteries is a common cause of death in Western society. The wall mechanics and haemodynamics within the arteries are considered to be important factors in the disease formation process. This paper is concerned with the development of an efficient computer-integrated technique to manufacture idealized and realistic models of diseased major and minor arteries from radiological images and to address the issue of model wall thickness variability. Variations in wall thickness from the original computer models to the final castings are quantified using a CCD camera. The results found that wall thickness variation from the major and minor idealized artery models to design specification were insignificant, up to a maximum of 16 per cent. In realistic models, however, differences were up to 23 per cent in the major arterial models and 58 per cent in the minor arterial models, but the wall thickness variability remained within the limits of previously reported wall thickness results. It is concluded that the described injection moulding procedure yields idealized and realistic castings suitable for use in experimental investigations, with idealized models giving better agreement with design. Wall thickness is variable and should be assessed after the models are manufactured.

Study on Three-Way Pipe’s Internal High Pressure Forming Simulation

2013 ◽  
Vol 589-590 ◽  
pp. 517-522
Author(s):  
Shi Gang Wang ◽  
Fu Sheng Gao ◽  
Feng Lan Cheng ◽  
Qiang Guo
Keyword(s):  
High Pressure ◽  
Wall Thickness ◽  
Three Dimensional ◽  
Thickness Variation ◽  
Forming Simulation ◽  
Finite Element Software ◽  
Plastic Processing ◽  
Wall Thickness Variation ◽  
Dimensional Shape ◽  
Pressure Parameter

Internal high pressure forming is a kind of the modern plastic processing technology. Using liquid as the pressure transmitting medium, explore the effect of internal high pressure parameter on the three passing pipe technique, internal high pressure forming technique is applied on the three-dimensional shape parts deformation. In this study, we simulate the three-way pipe process by finite element software, analyze the forming force influence to the tube forming quality and get the changeable regulation of the pipe wall thickness with conclusion of the wall thickness variation, which provides the reference data and guidance for the actual production of the three-way pipe.

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